1. Technical Field
The present invention relates to an improved structure of an illumination device serving as a backlight source which has a simplified structure.
2. Description of Related Art
Backlight modules are widely adopted in electronic devices such as notebook computers, monitors, cell phones, or liquid crystal televisions. The display component installed in the electric device not able to emit light by itself is required a backlight module for serving as a light source.
A conventional backlight module consists of a light guide unit and a light source, for an electronic product having a thin case, LED is often adopted as the light source, and the light source often referred as a side view light source is installed at a lateral side (a light incident surface) of the light guide unit. A first surface of the light guide unit is installed with a reflection sheet, a second surface opposite to the first surface is served as a light output surface, and can be installed with a plurality of optical membranes composed of diffusion sheets or prism lens according to actual needs, then a frame is provided for enclosing the mentioned components. The light emitted by the light source projects into the lateral side of the light guide unit, a part thereof is reflected by the reflection sheet then in sequence passes through the diffusion sheets and the prism lens set on the light output surface so as to be outputted outwards the light guide unit.
As shown in FIG. 1, which is a conventional illumination device serving as a backlight module adopted in a touch-control type electronic product, and the structure thereof includes an upper thin film layer A, a lower thin film layer B, an insulation layer C, a light guide unit D and at least a light source E; corresponding surfaces of the upper thin film layer A and the lower thin film layer B are respectively installed with a first circuit A1 and a second circuit B1; the insulation layer C is installed between the upper thin film layer A and the lower thin film layer for partitioning the first circuit A1 and the second circuit B1; the insulation layer C is formed with through holes C1 corresponding to plural electric conduction joints formed on the first and second circuits A1 and B1, accordingly when pressing the upper thin film layer A at the locations corresponding to the electric conduction joints, upper electric conduction joints A2 of the upper thin film layer can penetrate the through holes and be in electrical contact with lower electric conduction joints B2 of the lower thin film layer. The light guide unit D is installed below the lower thin film layer B, the light source E is installed at a lateral side of the light guide unit D, so the light of the light source E being input and transferred in the light guide unit can penetrate the lower thin film layer B, the insulation layer C and the upper thin film layer A. The mentioned illumination device can be adopted to serve as a backlight source in an electronic product such as a keyboard of notebook computer, a cell phone, various types of dashboards, a clock, a watch or a digital photo frame.